The researchers call for experimental studies to further examine the relationship between vitamin D, bone mineral density, and BPPV. Source. Talaat H., et al. Low bone mineral density and vitamin D deficiency in patients with benign positional paroxysmal vertigo. European Archives of Oto-Rhino-Laryngology, 2014.
Columnar epithelium forms the lining of the stomach and intestines. Some columnar cells are specialized for sensory reception such as in the nose, ears and the taste buds of the tongue. Goblet cells (unicellular glands) are found between the columnar epithelial cells of the duodenum.
Skin cells as well as those that line the stomach and intestines are continually being replaced. Surprisingly, then, epithelial tissue lacks blood vessels and must get its nutrients from underlying connective tissues. Because epithelial tissue covers surfaces and lines cavities, it always has a free surface. The other surface is attached to underlying tissue by a layer of carbohydrates and proteins called the basement membrane. Epithelial tissues are classified according to the shape of the cells and the number of cell layers.